Patellofemoral Pain Syndrome: Symptoms and Treatment

01Front knee pain

What patellofemoral pain means

The name refers to the joint between the kneecap (patella) and the thighbone (femur). Mayo Clinic describes patellofemoral pain syndrome as pain in the front of the knee, around or behind the kneecap, caused by pain in the soft tissues and bone around it. The kneecap helps protect the knee joint and plays a role in how the knee bends and straightens.

NHS inform describes it as a leading cause of chronic knee pain. It can affect one or both knees and often starts slowly. Mayo Clinic notes it is sometimes called runner’s knee and is more common in people who run or play sports with running and jumping; our guide on runner’s knee focuses on that running context, while this guide covers the condition more broadly.

02Symptoms

Symptoms during loaded knee bending

Symptoms vary from person to person. Mayo Clinic and NHS inform describe:

• a dull pain or ache beneath or around the kneecap
• pain going up or down stairs, kneeling, squatting, running or jumping
• pain after sitting for a long time with the knees bent, for example driving or at the cinema
• clicking, popping, crackling or grinding in the knee
• the knee giving way, or a feeling that it might
• some swelling, and a tight feeling in the calves and thighs

The common thread is that pain increases when the knee bends while carrying body weight, which puts more pressure through the joint behind the kneecap.

03Contributing factors

Load changes and contributing factors

NHS inform explains that the causes vary, but the condition is often the result of altered loading of the kneecap. Mayo Clinic adds that it usually happens when the kneecap does not move smoothly as the knee bends and straightens. Factors the two sources mention include:

• overuse from running and jumping sports, and sudden increases in activity, such as longer or more frequent workouts
• weakness in the buttock, hip and thigh muscles, and tightness in the hamstrings and calves
• the knee moving inward during a squat, which Mayo Clinic says has been linked to this pain
• repeated kneeling or bending of the knee, and sitting or driving for long periods
• being overweight
• a previous injury to the kneecap, or knee surgery, particularly some ligament reconstructions

Mayo Clinic also notes that it typically affects teenagers and young adults and is about twice as common in females. These are risk factors, not a verdict: having one of them does not mean you will develop the condition or that your technique is to blame.

04Differential

PFPS versus cartilage damage and other knee problems

Patellofemoral pain syndrome is not the same as damaged cartilage. Mayo Clinic explains that a separate condition, chondromalacia patellae, which is damage to the cartilage under the kneecap, can also cause pain at the front of the knee. PFPS is pain in the tissues around the kneecap and does not require cartilage damage. Our guide on knee cartilage damage covers that condition.

Mayo Clinic adds that in older people, arthritis is more often to blame for knee problems. Pain at the front of the knee can also come from the tendon below the kneecap, covered in our guide on patellar tendonitis. Because these conditions overlap, a professional assessment is the way to tell them apart.

05Reassessment

When swelling, locking or worsening need assessment

NHS inform lists some swelling and a feeling of giving way among possible symptoms, so they do not automatically mean something else. But the sources set clear points at which to seek or repeat a professional assessment:

• knee pain that does not improve within a few days, or a knee that becomes harder to move (Mayo Clinic)
• new or ongoing symptoms, so that the problem is diagnosed by a professional (NHS inform)
• symptoms that get worse, or no improvement within six weeks of following the advice (NHS inform)
• pain after an injury, particularly if the kneecap seemed to slip out of place, since Mayo Clinic links trauma to the kneecap and its cartilage with this pain

A knee that will not move freely, or swelling that is marked or getting worse, is not a reason to keep pushing through exercises: have it checked first.

06Diagnosis and imaging

Clinical diagnosis and when imaging may be useful

NHS inform’s advice is written for people who have been diagnosed by a healthcare professional, and it recommends seeing one for new or ongoing symptoms. It is useful to tell the professional where the pain is, which activities trigger it, any recent change in training or work, and previous injuries or surgery, because these are the factors the sources link to the condition.

Neither source presents scans as a routine part of diagnosing PFPS. Whether imaging such as X-ray or MRI is used is a decision for the clinician based on the history and examination. A single test or a home check cannot confirm or exclude the condition on its own.

07Treatment

Activity changes and individualized hip and knee exercise

According to NHS inform, the strongest evidence supports strengthening weak or underactive muscles and stretching short or tight ones. A key step is identifying which activities cause or increase your pain and modifying them while staying active, for example:

• reducing the amount of kneeling
• taking regular breaks during aggravating activities
• reducing the time spent sitting still

Mayo Clinic notes that simple measures such as rest and ice often help, but that some people need physical therapy. It highlights strengthening the leg and hip muscles, especially the outer hip and core, to help keep the knee from caving inward when you squat, land or step down, avoiding deep squats in weight training, warming up, gentle stretching, building up training slowly and wearing shoes that fit and suit the activity.

NHS inform adds that pain medicine can help you move more comfortably, and that you do not need to be free of symptoms to return to work; returning as soon as you can and gradually resuming daily activities helps recovery. Which exercises, how many and how hard depends on the individual, which is why a plan adjusted after assessment works better than a generic routine.

For adults with a diagnosed or suspected PFPS and no warning signs, our physiotherapy practice in Bilbao offers assessment and an individualized exercise plan (consultations are in Spanish).

08Recovery

Realistic recovery and a task-response record

NHS inform says that by following this advice you should see gradual improvement over time, and that you should talk to a healthcare professional if symptoms have not improved within six weeks or get worse. Neither source gives a fixed recovery time, and it varies with how long the pain has been present and how much the aggravating activities can be adjusted.

A simple record helps you and your physiotherapist adjust the load. For each task that matters to you, note:

• the task and how much you did: stairs, a walk, a run, squats, time sitting
• pain during the task on a scale from 0 to 10
• how the knee felt the next morning compared with usual
• any swelling, giving way or difficulty moving the knee
• changes in training, work or footwear that week

Sharing this record helps your physiotherapist decide which tasks to keep, progress or adjust. NHS inform also notes that looking after your mental wellbeing matters, as it can affect recovery.

09Sources

Where the sources differ

The two sources emphasize different first steps. Mayo Clinic mentions rest and ice as simple treatments that often help, whereas NHS inform stresses modifying aggravating activities while remaining active, with strengthening and stretching as the best-supported treatment. They also give different time frames for seeking help: Mayo Clinic advises calling a professional if pain does not improve within a few days, and NHS inform advises reassessment if there is no improvement within six weeks of following its advice, which assumes a diagnosis has already been made.

Mayo Clinic suggests that females may be more affected because a wider pelvis changes the angle at which the knee bones meet, and presents this as a possibility rather than a proven cause. NHS inform does not mention pelvic shape and focuses on muscle strength, flexibility and load. Body shape alone does not determine who develops the condition.

Both pages are recent: the Mayo Clinic page is dated September 2026 and the NHS inform page was updated in July 2026. NHS inform states that one in three adults may experience chronic knee pain at some point; that figure refers to knee pain in general, not to this condition alone.

10Summary

In summary

Patellofemoral pain syndrome causes pain around or behind the kneecap that is worse on stairs, squatting, kneeling, running or after long periods of sitting. It is linked to how the kneecap is loaded, with overuse, sudden increases in activity and weak or tight muscles around the hip and knee as common contributors. It is not the same as cartilage damage.

Treatment centers on adjusting aggravating activities while staying active and on individualized strengthening and stretching, with pain relief if needed. Improvement is usually gradual. Get the knee assessed if pain does not settle, worsens, follows an injury or the knee becomes hard to move, and use a record of tasks and next-day response to guide progress.